This invention relates to ultrasonic transducers and especially to obtaining improved focussing and increased bandwidth in a single-element device.
Transducers are focussed by the use of a lens or by bending the piezoelectric element so as to direct the ultrasonic energy to a point. In the former category are buffer rod transducers which have a large lens made of quartz or some other suitable material. While this technique does provide a high degree of focussing, the thick lens introduces undesirable reflections of the sonic beam which interfere with the received signal.